Hazar, VolkanTezcan Karasu, Gulsunozturk, GulyuzKupesiz, AlphanAksoylar, Serapozbek, NamikGokce, Muge2025-05-102025-05-1020211397-31421399-304610.1111/petr.13942https://doi.org/10.1111/petr.13942https://hdl.handle.net/20.500.14720/6964Uckan Cetinkaya, Duygu/0000-0003-3593-6493; Kocak, Ulker/0000-0002-8701-5285; Karakukcu, Musa/0000-0003-2015-3541; Karasu, Gulsun/0000-0001-5700-5919; Yesilipek, M.Akif/0000-0002-4514-8637; Karagun, Barbaros Sahin/0000-0002-7678-5524; Hazar, Volkan/0000-0002-1407-2334; Uygun, Vedat/0000-0003-3257-7798; Fisgin, Tunc/0000-0003-4467-9935; Akcay, Arzu/0000-0003-0841-1667; Aksu, Tekin/0000-0003-4968-109XBackground Post-transplant relapse has a dismal prognosis in children with acute leukemia undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). Data on risk factors, treatment options, and outcomes are limited. Procedure In this retrospective multicenter study in which a questionnaire was sent to all pediatric transplant centers reporting relapse after allo-HSCT for a cohort of 938 children with acute leukemia, we analyzed 255 children with relapse of acute leukemia after their first allo-HSCT. Results The median interval from transplantation to relapse was 180 days, and the median follow-up from relapse to the last follow-up was 1844 days. The 3-year overall survival (OS) rate was 12.0%. The main cause of death was disease progression or subsequent relapse (82.6%). The majority of children received salvage treatment with curative intent without a second HSCT (67.8%), 22.0% of children underwent a second allo-HSCT, and 10.2% received palliative therapy. Isolated extramedullary relapse (hazard ratio (HR): 0.607, P = .011) and relapse earlier than 365 days post-transplantation (HR: 2.101, P < .001 for 0-180 days; HR: 1.522, P = .041 for 181-365 days) were found in multivariate analysis to be significant prognostic factors for outcome. The type of salvage therapy in chemosensitive relapse was identified as a significant prognostic factor for OS. Conclusion A salvage approach with curative intent may be considered for patients with post-transplant relapse, even if they relapse in the first year post-transplantation. For sustainable remission, a second allo-HSCT may be recommended for patients who achieve complete remission after reinduction treatment.eninfo:eu-repo/semantics/closedAccessAcute LeukemiaChildrenPost&#8208Transplant RelapseTreatmentArticle255Q4Q233320995WOS:000598672000001